In the construction of traffic-bearing or pavement structures such as roads, bridges, parking decks, etc., using large masses of rigid construction material such as Portland cement concrete, it is well known that joints must be provided for between the rigid masses at regular intervals to allow for movement of the rigid masses due to stresses caused by traffic, changes in temperatures, etc. In construction of this type moreover where a relatively large degree of movement is expected, for instance in elevated structures such as bridge and parking decks, so-called "expansion" joints are conventionally provided for between the concrete masses which joint spaces can be up to about 3 to 4 inches in width.
Such joints or openings must be sealed in some manner in order to allow for smooth passage of traffic over the joint and/or to prevent foreign substances such as water, dirt, stones, etc., from entering the joint. The means utilized to seal the joint must be able to accommodate movement of the respective concrete bodies either horizontally and/or vertically with respect to one another. The joint-sealing means must also be able to withstand traffic thereover for reasonable lengths of time.
The most popular methods of sealing such expansion joints in road bridges, parking decks, etc. make use generally of either a pair of coacting, opposed, comblike steel members each locked to opposite edges of the separated concrete masses, or utilize a flexible, water-resistant joint-spanning member in the form of a continuous strip of synthetic elastomeric material, e.g. neoprene rubber, polyvinyl chloride, etc. The opposed, interfitting steel member-type joints provide for somewhat smooth passage of traffic thereover and accommodate movement, but usually permit passage of water and fine solids therethrough. Therefore these joints must be used in conjunction with some means of draining this water and fines below. This type of joint is obviously relatively expensive and subject to the corrosion of the metallic members.
Expansion joints using flexible joint-spanning members in the form of continuous strips are more economic than the interfitting steel member types. Most popular are joints which utilize tough preformed, flexible, hollow neoprene members which have the added advantage of preventing passage of water, sand, dirt, stone and road salts which in particular have a corrosive effect on reinforcing steel used in the concrete bodies. Such flexible sealing members may be simply forced into formed or sawed joints in the concrete bodies while the members are in a compressed state, the elastic properties of the sealing member serving to hold the member in place in the joints. In this case however the member is subject to becoming loose should the joint expand to a greater degree than expected. Also, the member is subject to being "sucked out" of the joint by traffic passing thereover.
Methods for anchoring such flexible joint-spanning members to the respective opposed concrete bodies of the joint have also been developed. In one popular method, exemplified in U.S. Pat. No. 3,598,026 to Johnson, the flexible sealing member has portions of its lateral edges secured into heavy metal anchoring members embedded into the opposed concrete bodies. The edges are shaped such that they resist withdrawal from the metal anchors. The metal anchors ideally resist the heavy stresses placed upon them by vehicular traffic passing over the joint. Metallic anchoring members however are expensive to manufacture, and are also costly to install since they usually require welding or drilling operations. Metal is moreover subject to corrosion, and corroded anchors are expensive to repair or replace. In a more recent expansion joint-forming method exemplified in U.S. Pat. No. 3,981,601 to Arai, the lateral edges of the flexible joint-spanning member have openings preformed therethrough to receive bolts which anchor the flexible member to metallic members secured in the concrete. Again the use of such metal anchoring systems is relatively expensive. Also in the system shown in U.S. Pat. No. 3,981,601, the flexible sealing member is exposed to vehicle traffic which will cause the seal to wear at the portions where the seal is forced against the shoulders of the concrete bodies.